Lubricating device for pump-pistons



J.. W. DREW. LUBRICATING DEVICE FOR PUMP PISTONS. APPLICATION FILED FEB.28, 1921.

1,390,680. Patented-Sept 13, 1921;

M/VE/VTO'R JOHN WDREW l ing-drawings, forming part of this specifica- ,UNITEDSTATES PATENT OFFICE,

JOHN w. nanw. or s'r. ouis; mssouar, assxononro moon nnornsnsmanumcroams comrm, or sr. LOUIS, mssounr, a conronarron or mssouar.

LUhRIGATmQP FOR I MrT To all whom itwmy concern/k. Y i 1 Be it known that I. JoHN DREW, a citizen of the United States, residing at St. Louis, Missouri, have invented .a certain new and useful Improvement in Lubricating Devices for Pump-Pistons, of which the following is a full, clear, and exact description, such will enable others skilled in the art to which it appertains to make and use the same, reference being bad to the accompanytion, in whichi Figure 1 is a vertical sectional view through a portion of a pump cylinder showing my improved piston ositioned therein.

Fig. 2 is a plan view 0 the piston.

' Fig. 3 is a sectional view of the piston 1 head with the parts separated.

This invention relates to new and useful improvements in istons for air pumps, being designed articularly for air pumps of the type emp oyed for the inflation of hicycle and automobile tires and which are usually operated by hand.

The object of this invention is to make a pump of this type more eflicient by providing a simple and effective lubricating means for the piston, and which can be cheaply manufactured and add but few'extra parts tothe structure.

In the drawings,1 indicates the cylinder of the pump, 2 the piston rod which is reduced near its lower end to form a shoulder 3. 4 is a sleeve designed to fit the reduced ortion of piston rod 2, said sleeve being lield in position by a nut 5. In the lower end of sleeve 4 is an enlarged annular ring 4 upon which rests a metallic retaining washer 6, which in turn acts as a support for a cup-shaped member 7 made of fibrous ma terial, and a second and slightly larger guiding washer 8 rests on top of the fibrous cup-shaped member 7. 9 is one or more washers made of some fibrous "material, preferably felt, these washers having a diameter correspondi to the inner diameter of the cylinder 1. ibrouswashers 9 rest on metallic washers 8 and are held in place by a cup-shaped metallic member 10 which as an inwardly disposed flange 10' which bears against sleeve 4 and an outwardly disposed flange 10 which holds the fibrous washers com actly in position.

T e upper end of sleeve 4 is beveled sh that it may be knurled or spun over the l specifitiation of Letters fateliti i Application filed February 28, 1921. SerialNo.448,564.

I at-ented Sept.

flange 10, thus making a unit of the group supported by said sleeve,'z'. e., the retaining washer 6,. the leather cup 7, the guiding washer 8, the felt washers 9, and the cupshaped member 10. A series ot holes 11 are made through this unit, said holes being approximately parallel-to the axis of the piston rod 2..

A washer 12 of leather or similar material which. acts as a valve is placed on the annular ring 4 of sleeve 4. This valve member is permitted to move freely on the annu lar ring of the sleeve and is prevented from coming off by nut 5, which clamps the sleeve and its carried parts in position on the rod.

The fibrous washers 9 are soaked with'a lubricant so that when the piston moves in pumping the air, small particles of the lubricant are continually being left along the wall of the cylinder. These particles oflubricant that adhere to the cylinder make the friction of the piston less and help make the pump more eflicient by sealing or partially sealmg the leather cup against the cylinder. Advantage is taken of capillary attraction. Since the lubricant is an attracted liquid, it

will be distributed throughout the fibrous washers at all times, thus insuring long lubricatingqualities to the washers.

In the suction stroke, the air passes through the openings 11, strikes against the valve 12 and since valve 12 is movably arranged on annular ring 4, it will permit the free passage of air into the chamber beneath the piston. In the compression stroke of the piston, the air below thepiston reseats the valve 12 so that the openings 11 are effectively closed. During both suction and compression strokes of the iston, particles of the lubricant from the fi rous washers 9 are continually being deposited on the wall of the cylinder by capillary attraction.

A spring 13 may be placed on the piston rod 2 in order to absorb the shock that might occur at the extreme end of the suction stroke if the iston was suddenly drawn up against the cy inder head by such movement.

I claim:

1. In a piston, the combination of a piston rod, a leather cup-shaped washer fixed thereon, metallic washers arranged above and below said leather cup-shaped washer, uninterrupted air holes through said members, a leather valve member arranged to control one end of said air holes, a fibrous 1ubrieating washer juxtaposed against one of said metallic Washers and provided With a central opening-of-larger diameter than said registering air holes, and a cup-shaped metallic Washer fixed to said p'iston rod for holding said fibrous washer in fixed position, said cup-shaped Washerv being also provided With registering air holes.

2. In a piston, the combination-of. a piston rod having a reduced end portion forming a shoulder; a sleeve member mounted on the reduced portion of said piston rod and having an annular enlargement on one end thereof 'a retaining Washer seated against said enlargement, a leather cup-shaped memvsignature this 25th day of February, 1921.

JOHN W. DREW. 

